Thorny River Project
Thorny River is BMIN’s flagship project in South Africa—a kimberlite dyke system with localised “blows” that have been explored since 2017. Situated in Limpopo Province, approximately 6 km from the Marsfontein mine and 6 km from Klipspringer, it has undergone extensive geophysical exploration, drilling, trenching, and bulk sampling. This work resulted in a Competent Person’s Report (“CPR”) and a Technical Economic Evaluation (“TEE”), which define the exploration target and assess mining options.
The CPR estimated a kimberlite target of 1.2–2.1 million tonnes, with modelled grades of 46–74 cpht and diamond values of $120–220/ct (+1mm cut-off, 2017 values). Geologically, Thorny River aligns with the same dyke system as Klipspringer and Marsfontein, both high-grade producers. BMIN’s sampling confirmed comparable diamond quality and grade potential.
A conceptual open-pit study by Practara (Pty) Ltd and ABGM assessed various price and cost scenarios. Even at a conservative 20 cpht and $170/ct, the model produced a positive NPV(10%), while the optimal case, 50 cpht and $170/ct, showed an NPV(10%) of nearly US$98 million. These findings indicate that Thorny River could be a profitable small mine, especially with stronger diamond prices.
Following these findings, BMIN prioritised permitting and mine readiness. By 2024, two Mining Permit applications covering the River and River Extension blows had been submitted; one received Environmental Authorisation, the final prerequisite. On 6 March 2025, BMIN announced the granting of the first Mining Permit, enabling mining to commence in that zone, while the second permit remained in progress. This milestone marks Thorny River’s transition from evaluation to potential development.
